Wednesday, August 18, 2010

Tropical Plant Fats: Coconut Oil, Part I

Traditional Uses for Coconut

Coconut palms are used for a variety of purposes throughout the tropics. Here are a few quotes from the book Polynesia in Early Historic Times:
Most palms begin to produce nuts about five years after germination and continue to yield them for forty to sixty years at a continuous (i.e., nonseasonal) rate, producing about fifty nuts a year. The immature nut contains a tangy liquid that in time transforms into a layer of hard, white flesh on the inner surface of the shell and, somewhat later, a spongy mass of embryo in the nut's cavity. The liquid of the immature nut was often drunk, and the spongy embryo of the mature nut often eaten, raw or cooked, but most nuts used for food were harvested after the meat had been deposited and before the embryo had begun to form...

After the nut had been split, the most common method of extracting its hardened flesh was by scraping it out of the shell with a saw-toothed tool of wood, shell, or stone, usually lashed to a three-footed stand. The shredded meat was then eaten either raw or mixed with some starchy food and then cooked, or had its oily cream extracted, by some form of squeezing, for cooking with other foods or for cosmetic or medical uses...

Those Polynesians fortunate enough to have coconut palms utilized their components not only for drink and food-- in some places the most important, indeed life-supporting food-- but also for building-frames, thatch, screens, caulking material, containers, matting, cordage, weapons, armor, cosmetics, medicine, etc.
Mainstream Ire

Coconut fat is roughly 90 percent saturated, making it one of the most highly saturated fats on the planet. For this reason, it has been the subject of grave pronouncements by health authorities over the course of the last half century, resulting in its near elimination from the industrial food system. If the hypothesis that saturated fat causes heart disease and other health problems is correct, eating coconut oil regularly should tuck us in for a very long nap.

Coconut Eaters

As the Polynesians spread throughout the Eastern Pacific islands, they encountered shallow coral atolls that were not able to sustain their traditional starchy staples, taro, yams and breadfruit. Due to its extreme tolerance for poor, salty soils, the coconut palm was nearly the only food crop that would grow on these islands*. Therefore, their inhabitants lived almost exclusively on coconut and seafood for hundreds of years.

One group of islands that falls into this category is Tokelau, which fortunately for us was the subject of a major epidemiological study that spanned the years 1968 to 1982: the Tokelau Island Migrant Study (1). By this time, Tokelauans had managed to grow some starchy foods such as taro and breadfruit (introduced in the 20th century by Europeans), as well as obtaining some white flour and sugar, but their calories still came predominantly from coconut.

Over the time period in question, Tokelauans obtained roughly half their calories from coconut, placing them among the most extreme consumers of saturated fat in the world. Not only was their blood cholesterol lower than the average Westerner, but their hypertension rate was low, and physicians found no trace of previous heart attacks by ECG (age-adjusted rates: 0.0% in Tokelau vs 3.5% in Tecumseh USA). Migrating to New Zealand and cutting saturated fat intake in half was associated with a rise in ECG signs of heart attack (1.0% age-adjusted) (2, 3).

Diabetes was low in men and average in women by modern Western standards, but increased significantly upon migration to New Zealand and reduction of coconut intake (4). Non-migrant Tokelauans gained body fat at a slower rate than migrants, despite higher physical activity in the latter (5). Together, this evidence seriously challenges the idea that coconut is unhealthy.

The Kitavans also eat an amount of coconut fat that would make Dr. Ancel Keys blush. Dr. Staffan Lindeberg found that they got 21% of their 2,200 calories per day from fat, nearly all of which came from coconut. They were getting 17% of their calories from saturated fat; 55% more than the average American. Dr. Lindeberg's detailed series of studies found no trace of coronary heart disease or stroke, nor any obesity, diabetes or senile dementia even in the very old (6, 7).

Of course, the Tokelauans, Kitavans and other traditional cultures were not eating coconut in the form of refined, hydrogenated coconut oil cake icing. That distinction will be important when I discuss what the biomedical literature has to say in the next post.


* Most also had pandanus palms, which are also tolerant of poor soils and whose fruit provided a small amount of starch and sugar.

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